1. Field of the Invention
The present invention relates to a method for replacing a program stored in portable information terminal equipment, and more particularly, to a method for replacing a program stored in a program storage unit of a portable information terminal using a communication unit.
2. Description of Related Art
In general, a portable information terminal operating as a multi-media product having many functions (e.g., a cellular phone, a wireless facsimile, a wireless pager, and an electronic pocketbook) can search for information at any time or place while being carried in a user's hand, and transmit and receive data by being connected to external devices such as a computer.
The portable information terminal cannot provide as many functions as a computer, since it must be manufactured as small as possible, and can run only a small program because of its small memory capacity. That is, portable information terminals generally include a small-capacity ROM (read only memory) or EPROM (programmable ROM), and a random access memory (RAM) or a personal computer memory card industry association (PCMCIA) card. Although the ROM is low-priced, a program stored therein cannot be changed. On the other hand, a program stored in a RAM can be easily be changed, but the RAM is expensive and prone to damage by events such as power failure. Likewise, the PCMCIA card is expensive. As a result of the small memory capacity, the portable information terminal must be able to add a new program or replace a prestored program with a new program, as needed.
FIG. 1 shows the configuration of a conventional portable information terminal which is disclosed in U.S. Pat. No. 5,590,373. A new program which is to replace a prestored program in a ROM 122 is recorded in a PCMCIA card 126. Also, a utility program operates to replace the prestored program recorded in the ROM 122 with the new program. The utility program is executed by being transferred through a PCMCIA receptacle 124 to a RAM 128 together with the new program. A particular bit combination in an option connector 120 informs a controller 130 that the PCMCIA card 126 having the new program recorded therein is being inserted into the terminal's main body. At this time, the controller 130 transfers the utility program in the PCMCIA card 126 to the RAM 128 and then executes the transferred utility program. Here, the utility program operates to replace the prestored program in the ROM 122 with the new program in the PCMCIA card 126. A decoder 116 interprets an option of the option connector 120. A power supply 112 supplies current to a static current generating device (not shown) of the option connector 120 through a connector receptacle 118. A program replacement method in the conventional portable information terminal cannot be applied to equipment which does not include the PCMCIA card 126. Further, special units such as the option connector 120 and the connector receptacle 118 are required to begin replacing the program in the ROM 122.